Vehicle doors are typically constructed with two or more panels attached to the door frame, including an exterior or outer panel for shielding the passenger compartment from the elements, and an inner door panel which provides structural support. A trim panel is usually fastened to the inner door panel facing the passenger compartment and shields the vehicle occupants from internal door components, such as the window, the window regulator, and the door locks. The trim panel can also provide aesthetic qualities to the interior passenger compartment as well as ergonomic features, for example, easily accessible door handles, mirror and window controls, and the like.
To lessen the effects of a side collision type impact of the vehicle occupant seating area, some vehicle door constructions may include a door intrusion guard beam, side bolsters of foam or honeycomb construction, or other body side structural upgrades. Positioning of these devices often depends on vehicle door design, but takes into account the spatial relationship of an occupant seating area adjacent the door. In vehicle door designs in which the guard beam is laterally aligned with an energy absorbing bolster, a side impact collision may cause localized deformation of the bolster potentially decreasing its energy absorption effectiveness. This results since the guard beam typically has a smaller occupant facing cross-sectional area than the bolster.